This invention relates to thermal conditions in computer systems and, more particularly, to addressing critical thermal conditions.
A processor-based system includes a system board, sometimes known as a motherboard, populated with a great many integrated circuits, or ICs. These ICs operate by receiving power, at which time they may each independently generate a number of signals. Accordingly, a processor-based system""s motherboard is generally connected to a central power supply.
For very large-scale integrated circuits, such as processors, a huge number of operations may be performed. Likewise, as clock speeds increase, the operations are performed at very fast rates. Accordingly, the processor may build up a tremendous amount of heat, which may degrade its performance. The distribution of power, and thus the control of the temperature of the processor is a paramount consideration for the motherboard designer.
As processors are built on smaller chips and run at faster clock rates, protecting the processor from over-heating remains a critical design consideration. The complexity and capability that once only mainframes could provide is today available on system boards that may fit in a shirt pocket. Technologies such as laptop computers, cellular telephones, personal digital assistants, digital cameras, and so on, contribute to this ever-greater demand for smaller system boards.
One mechanism for controlling the temperature of a processor on a motherboard is to attach a cooling fan to the motherboard. Another solution is to add a xe2x80x9cheat sinkxe2x80x9d to the processor. The heat sink helps to dissipate heat from the processor during operation.
Despite these prophylactics, the processor on the motherboard may exceed a desired temperature. Once this threshold has been surpassed, the processor may fail or degrade in performance. Likewise, other ICs as well as non-ICs, such as hard disk drives, may suffer in performance if operated beyond certain temperature thresholds.
Some processor-based systems include firmware, operating systems, or other application software which monitors temperature conditions. These intelligent systems may address the temperature condition in any of a number of ways. For example, according to the Advanced Configuration and Power Interface specification (ACPI), an operating system monitors and responds to temperature conditions. The ACPI Specification, Revision 1.0, was published by Intel, Microsoft, and Toshiba, in December of 1996.
According to the ACPI specification, in response to a first temperature condition, the operating system may slow down operation of the processor clock, known as clock throttling. Upon receiving a next, ostensibly higher, temperature condition, the operating system may turn on a fan connected to the motherboard, and then may subsequently turn off one or more of the operating devices.
At a third temperature condition, known as a critical temperature point, the operating system performs an orderly shutdown of the system and finally disables power to the system. During orderly shutdown, the operating system may render motherboard circuitry and peripheral devices to a known state and may close any running software programs.
The above hardware and software solutions may address the majority of temperature conditions for a processor-based system. However, increasingly, processor-based systems may be subjected to environments in which temperatures may not be anticipated by system designers. In particular, highly mobile devices, such as cellular telephones, may be operated wherever people are found. In some temperature environments, the success or failure in saving an integrated circuit may turn on the speed at which the temperature condition is addressed.
Thus, there is a continuing need to more effectively address critical temperature conditions in processor-based systems.